1. Field of the Invention
The present invention relates to a display device wherein a memory circuit is installed in each pixel, and an electronic device using the same.
2. Description of the Related Art
For a conventional display device having a plurality of pixels arranged in a matrix formed by rows and columns, when an image is displayed, data is written to the pixels by a driver under an image display mode or dynamic image display mode. Especially, when a static image is displayed, the same data is continuously written to the pixels. Therefore, a technique is provided, wherein a memory is installed in each pixel so that when a static image is displayed, the data stored in the memory is written to the pixel. In this regard, driving of the driver can be stopped to reduce power consumption. This technique is usually called an MIP (Memory in Pixel) technique.
Generally, in the MIP technique, a memory circuit for storing data is adopted with a DRAM (Dynamic Random Access Memory) or an SRAM (Static Random Access Memory). The SRAM is constituted by a transistor sequential circuit. On the other hand, the DRAM is constituted by a transistor and a capacitor. Therefore, in view of minification of the circuit area and narrowing of the pixel gap, the DRAM is preferred. However, a DRAM needs a refresh operation to hold tiny electric charges stored in the capacitor. An example for a pixel circuit using DRAM is described in International publication no. 2004/090854(A1) pamphlet (Patent document 2).    Patent document 1: Japanese Patent Application Publication no. 2007-328351    Patent document 2: International publication no. 2004/090854(A1) pamphlet
However, in a normally black type liquid crystal display device, which displays black color when no voltage is applied to the liquid crystal cell, if a DRAM is used to construct the MIP circuit, flicker would occur while white color is displayed.
The invention provides a display device wherein a memory circuit is installed in each pixel but flicker does not occur, and an electronic device using the same.